Treasurer Wayne Swan has defended describing Australia's multi-billion-dollar deficit as "temporary" after it was revealed that the Budget will stay in the red for at least the next six years.

Government sources yesterday confirmed that Treasury has told the Government that the Budget would not be able to return to surplus until the 2015-16 financial year.

The deficit is expected to be around $60 billion and Government revenue will also take a $200 billion hit over the next four years.

Since conceding late last year that the Budget would go into deficit, the Government has described the fall into negative territory as a "temporary" measure to be taken over the "economic cycle".

Mr Swan has told ABC 2 News Breakfast the deficit is temporary because the Government has a plan to return the Budget to surplus.

"We have a very clear determination to return our Budget back to surplus in a responsible way and to make sure that it is sustainable for the long term," he said.

He says the length of the economic cycle is dependent on global conditions.

"The cycle has been lengthened by the dramatic collapse in demand globally," he said.

When asked if the Government was entering "Yes Minister territory" over its definition of temporary Mr Swan replied; "No we certainly are not, I beg to differ with you."

The Government has been warning it will hand down a tough Budget next week amid speculation savings will be made by cutting middle-class welfare and high-income earners will be slugged to fund an increase to pensions.

Reports today say the amount high income earners can salary sacrifice to superannuation will be halved from $100,000 to $50,000 for people aged over 50, and from $50,000 to $25,000 for those under 50.

Mr Swan says the Government must make make savings.

"There will be tough decisions to make room to meet our commitment to pensioners but also to make those vital investments for the future. I think every one is going to have to do their bit in this Budget," he told AM.

Opposition Leader Malcolm Turnbull yesterday ridiculed the Government over its insistence that the deficit is temporary.

"I have very grave doubts - very, very grave doubts - whether Mr Swan or Mr Rudd will ever preside over a surplus budget," he said.

And today Opposition treasury spokesman Joe Hockey said Government spending was to blame for the high deficit.

"Australians need to be aware that this means that every Australian is going to have to work longer, harder, for less money and the bottom line is that every Australian for a generation if not longer is going to have to pay off Kevin Rudd's debt," he told 2UE.